FSHB encodes follicle-stimulating hormone beta subunit, a critical reproductive hormone component. Together with the alpha chain CGA, FSHB forms follitropin (FSH), a glycoprotein heterodimer where the beta subunit determines biological specificity 1. FSH binds FSHR, a G protein-coupled receptor on target cells, activating downstream signaling cascades including MAPK pathways 2. In reproductive tissues, FSH stimulates follicle development, spermatogenesis, and steroidogenesis 3. FSHB gene expression represents the rate-limiting step for mature FSH production, regulated transcriptionally by GnRH signaling in gonadotropes 1. Beyond reproduction, FSH exhibits extragonadal roles in bone metabolism; FSHB variants and circulating FSH levels associate with osteoporosis risk through immune, lipid metabolic, and hormonal regulatory pathways 4. FSHB genetic variants (e.g., -211G>T) modulate FSH serum levels and testis size with modest effects on testicular function in healthy men 5. Clinically, FSHB mutations cause hypogonadotropic hypogonadism with or without anosmia. FSHB also shows pleiotropic effects across female reproductive health diagnoses, including roles in folliculogenesis and hormonal regulation 6. The FSHB locus exhibits genomic stability as a single-copy gene in a gene-poor region, distinguishing it from the duplicated LHB/CGB loci 7.